Stent Apex Geometry for Reduced Lateral Deflection
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Solution Overview
Problem
Prostheses with stents often experience lateral deflection during deployment due to longitudinal compression, leading to increased friction with the lumen wall and potential failure in curved vessels, especially in delicate applications like cerebral vessels.
Innovation Solution
The design features shaped, planar apexes on stent members that prevent interdigitation and distribute longitudinal compression forces, reducing lateral deflection by maximizing contact area and distributing forces across the prosthesis, thereby minimizing friction and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the prosthesis is subjected to longitudinal compression during deployment, then the prosthesis can be maneuvered into the desired location, but lateral deflection occurs causing increased friction and deployment failure
Solution Approach 1:
The patent applies local quality by modifying only the apex portions of the stent members while leaving the rest of the stent structure unchanged. The shaped apex portions (flat, concave, or convex) are specifically designed to prevent interdigitation and reduce lateral deflection, while the remaining stent struts maintain their original configuration for radial expansion functionality.
Solution Approach 2:
The patent introduces asymmetry by creating non-uniform apex portions on the stent members. The apexes are shaped with specific geometries (flat surfaces, concave regions, or convex regions) that differ from the symmetric cylindrical shape of traditional stents. This asymmetric design prevents the interlocking of adjacent stent members during longitudinal compression, thereby reducing lateral deflection.
2Volume of moving object
If the stent members are closely spaced, then the prosthesis structure is more compact, but interdigitation of adjacent stent members occurs under compression
Solution Approach 1:
The patent applies local quality by modifying only the apex portions of the stent members while leaving the rest of the stent structure unchanged. The shaped apex portions (flat, concave, or convex) are specifically designed to prevent interdigitation and reduce lateral deflection, while the remaining stent struts maintain their original configuration for radial expansion functionality.
Solution Approach 2:
The patent applies preliminary anti-action by pre-shaping the apex portions of the stent members before deployment. The shaped apexes (with flat, concave, or convex surfaces) are designed in advance to counteract the interdigitation tendency that would occur during longitudinal compression, thereby preventing lateral deflection before it can occur during the deployment process.
3Strength
If the prosthesis is expanded radially to fit the lumen, then the prosthesis provides adequate support, but the profile is too large for introduction into the body lumen
Solution Approach 1:
The patent applies dynamics by designing the stent members with flexible connectors that allow the prosthesis to transition between different states. The stent can be compressed to a small profile for introduction through the catheter, then radially expanded at the deployment site to provide adequate vessel support. The shaped apexes maintain their functionality throughout this dynamic transformation.
Data Source
Figure 1
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AI summary
A prosthesis (110;210) comprises a plurality of stent members which are formed of strut elements (120) connected by apexes, wherein the proximal apexes (122;226a) of a first stent member (116a;216a) and the distal apexes (124;224b) of a second stent member (116b;216b) have a shaped portion which is flat or concave. The proximal apexes (122;226a) are arranged to engage the distal apexes (124;224b) when the prosthesis is subjected to longitudinal compression forces and the shaped portion of the apexes prevents interdigitation of the stent members. End marker elements (220,320) may have similarly shaped lateral extensions (222,322) arranged to engage the distal apexes (224a) of the first stent member.